Sunday, July 07, 2013

How Does Scherzer Look If We Add Hits To The Equation?

Tigers starter Max Scherzer is off to the best start of his career dominating American League hitters en route to a 13-0 record, 3.09 ERA and 2.63 FIP. Exactly how good has he been? If you like Win-Loss record, then he is off to the best start of any pitcher in 27 years. If ERA is your statistic of choice, then he is the ninth best pitcher in the American League. If you prefer FIP, then he is second to teammate Anibal Sanchez. So, there is no consensus among the measures other than to say he is somewhere between very good and the best pitcher in 27 years.

The limitations of all three measures have been discussed here before. Win-loss record is a team statistic heavily influenced by run support and is generally not a good way to evaluate individual pitchers. The ERA statistic is better but also has shortcomings such as:

ERA gives pitchers full credit/blame for results of batted balls in
play despite the fact that they share that responsibility with
fielders. For example, a pitcher with a strong defense behind him will
tend to give up fewer hits (and thus fewer runs) than if he has a poor
defense behind him.

ERA gives pitchers full responsibility for sequencing or timing of
events, that is, it assumes that they can control when they give up hits
and walks. For example, if a pitcher pitches extraordinarily well with
runners in scoring position in a given year, he will have a lower ERA
than if he had a typical year in those situations. Additionally, a
pitcher who tends to bunch base runners together in single innings will
have a higher ERA than if he had a typical year distributing base
runners more evenly.

In reality, pitchers have limited control over both the number of batted
balls that drop for hits and sequencing of events. Thus, Defense
Independent Pitching Statistics (DIPS) such as FIP, xFIP, tERA and
SIERA have been developed to remove some of the noise of ERA. DIPS are
based on things that pitchers do control for the most part - walks,
hit batsmen, strikeouts, home runs and types of batted balls (ground
balls , fly balls, line drives, pop flies).

Because they are based on things that pitchers essentially control, the
DIPS metrics are said to be better measures of true talent than ERA.
As a result, they are also better than ERA at predicting future
performance. However, they only measure a portion of a pitcher's talent
and should be used as complements to ERA rather than as replacements.

It is not known exactly how much control pitchers have on the results of
balls in play, but recent research tells us that some pitchers are
better than others at preventing hits on balls in play. For example, Mike Fast,
formerly of Baseball Prospectus and now a MLB sabermetrician, used
Sportsvision's hit f/x data to show how pitchers varied on the speed of
balls off the bat.

So, rather than making the big leap from ERA to FIP, it might be a good
idea meet half way. Instead of removing hit prevention and
sequencing in one step, it might be better to remove one factor at a
time. Bill James did that with his Component ERA
(ERC). Applying the runs created methodology to pitchers, he
determined what a pitcher's ERA should have been based on walks, hit
batsmen, strikeouts, homers AND hits allowed. I'm going to look at
some similar statistics here based on more modern measures such as
linear weights and Base Runs.

We often use Weighted On-Base Average (wOBA) to measure overall hitting
performance and it can also be used for pitchers. The American League
wOBA Against (wOBAA) leaders are shown in Table 1 below. Clay Buchholz of the Red Sox currently leads the league with a .242 wOBAA.
Scherzer is third in the league at 254. Another Tiger among the leader is Anibal Sanchez who is fifth at .269

It's generally a good idea to convert to runs allowed when trying to evaluate
pitchers and this can be done with the Base Runs measure created by
David Smyth in the early 1990s. The Base Runs metric is based on the idea that we can estimate team runs scored if we know
the number of base runners, total bases, home runs and the typical
score rate (the score rate is the percentage of base runners that score
on average). Base Runs also works well for individual pitchers. The
complete formula can be found here.

Table 2 shows that Scherzer has 35 Base Runs Against in 116 2/3 innings so far this
year. This means that he should have allowed an estimated 35 runs based
on the number of base runners, total bases and home runs he has
allowed. He has allowed 41 actual runs, so runs are scoring against him
at a higher rate than you would expect. That could possibly be
due to poor defense (which wouldn't be surprising for the Tigers), unfortunate timing or just bad luck on locations of
batted balls.

Scherzer has 22 Base Runs Above Average (RAA) which means that
he has saved the Tigers an estimated 22 runs compared to the average
pitcher in the same number of innings. Table 2 shows that he is second
in the league on that metric. White Sox southpaw Chris Sale leads the league with 23 RAA. Sanchez is eighth with 13 RAA. Doug Fister is listed at 12 RAA, but that does not include today's outing.

Finally, Table 3 shows that Scherzer has allowed 2.52 Base Runs per nine
innings. About 93% of runs are earned, so multiply this result by
.93. to put it on the same scale as ERA. The final result is a weighted
component ERA. Although, I am not using linear weights here,
I call it WERC because others have said they like the name.
It's really not a novel idea though. Patriot of Walk Like a Saber has been using Base Runs to evaluate pitchers for a while but prefers to not convert to the ERA scale.

Getting back to the example, Scherzer has a 2.52 WERC which places him third in the league behind Buchholz (2.08) and Sale (2.36). Because Scherzer's FIP and WERC are so similar, the discrepancy between ERA and
FIP would appear to be the result of sequencing rather than batted
balls. So, if there is any bad luck involved, it's probably timing.

Based on the above numbers, it would appear that Buchholz, Sale and Scherzer have been the best pitchers in the league this year. Like other metrics, none of these give the ultimate answer though. They do tell us where the pitchers stand if we add hits allowed to FIP though, a perspective which is often ignored.